This request is for funds to purchase an analytical bench top research two-laser flow cytometer. The new instrument, a BD FACSCalibur, will serve as the only analytical cytometer in Department of Environmental and Occupational Health (EOH) of the Graduate School Public Health (GSPH) and for users in nearby Magee Women's Research Institute (MWRI) who share common interests in environmental health science and additional work in maternal/child health. The rationale for this request includes: a) The Department of Environmental and Occupational Health (EOH) is in an extensive recruitment phase with an emphasis on contemporary environmental health science that greatly increases our utilization of flow cytometry. This expansion coincides with the recent recruitment of Dr. Jerry Schatten and colleagues at our Magee Women's Research Institute (MWRI) thereby greatly further expanding our user base; b) EOH is in a newly renovated stand alone facility 0.2 to 0.4 miles from collaborating investigators (with the noted exception of much closer proximity to MWRI) requiring transit through unacclimatized outdoor routes minimizing the opportunity to share flow cytometers located in several other departments in our allied health system; c) Our major Flow Cytometry Core facility, directed by Dr. Donnenberg, relocated (September 2002) to the Hillman Cancer Center that is 1.5 miles away adding, to our need to establish an independent ability to perform analytical flow cytometry; d) The instrument is vital for training of pre- and postdoctoral students; and e) An analytical flow cytometer (e.g., FACSCalibur) will provide valuable quantitative approaches to support more complex research protocols in environmental health science with the aid of our colleagues on our advisory committee from Flow Cytometry Core (Dr. Donnenberg) and Center for Biological Imaging (Dr. Watkins). Applications will include multicolor immunophenotyping, physiological studies on transfected cells, signaling and apoptosis, stem cell biology and microbiology.